1. Technical Field of the Invention
The present application, in a preferred embodiment, is directed to an airspace management system and method which includes an alternate "quick look" mode (QLM) display. This "quick look" display mode provides a controller of an airspace management system with an opportunity to view radar plots of aircraft in a particular designated area of the display screen. This allows for a display of aircraft within a dogfight for example, or of an aircraft on a landing approach for example, such that a special pathway can be provided for data in the quick look mode to generate a quick radar plot of the aircraft(s), bypassing a normal tracking processing function (which normally must process received input radar information (plots) to generate tracks and/or information other than a radar plot).
2. Description of Related Art
Known airspace management systems and automated air defense systems provided an operator or controller with information about aircraft based upon received radar information which had to be processed before display. The resulting information might have included digital symbology to distinguish a friendly aircraft from an enemy aircraft or foe at a glance via IFF/SIF (Identification Friend or Foe/Selective Identification Feature) mode and code; other identification information; coordinate location information; height information; and weapons guidance recommendations for example. The SIF permitted the controller to selectively display discrete IFF returns or symbols, to differentiate one friendly aircraft from another, in lieu of traditional track data blocks. However, these systems failed to provide the controller with meaningful support during a tactical engagement or "dogfight" for example, and further failed to provide a controller with information that might be particularly useful to control an aircraft on a landing approach, where controllers need immediate trend information on aircraft positions, in three dimensions, relative to glide slope and glide path.
During a period of tactical engagement, the symbology, data blocks, and intercept guidance recommendations that were previously useful now become a hindrance. Such information merely clutters a screen. Thus, much of the information previously indicated must be turned off (de-selected) by the controller. The controller, in a tactical engagement situation, requires only the information depicting the precise positions of fighters and targets.
Previously, automated airspace management systems and methods were not able to quickly and precisely display aircraft locations in situations such as a tactical engagement or in the control of an aircraft on an approach to a landing. In such a known system, such as that shown in FIG. 1, radar information was received from a radar sensor 1, for example, and an input data stream 5 was provided to a modem 7 at the airspace management facility 9. Further, an IFF sensor 3, associated with and triggered to provide a reading shortly before or after the radar sensor 1, further optionally contributed information to the input data stream 5 indicating friend or foe information identifying the aircraft. This information was received by modem 7.
After receiving the information in modem 7, an operations computer program (OCP) 11 then processed the data (X) output from the modem 7. As shown in an expanded portion of FIG. 1, the OCP 11 included an IFF and radar height measurement association unit 15; an associated plot unit 17; and a tracker unit 19. These functions or units could have been physically separated in different processors or physically combined in a single processor/work station. Processing of the received radar information will be discussed hereinafter with regard to the flowchart of FIG. 2, with a single target being discussed for the sake of clarity.
The data (X) from the modem 7 was received by the IFF and radar-measured height information association unit 15 in step S1 of FIG. 2 for example. This unit received data bit streams from radar sensor 1 (which may or may not have been multiple radar sensors, each provided at different locations), the data bit streams optionally including IFF (identification friend or foe) data bits and further optionally including radar-measured aircraft altitude information. The IFF and radar height information association unit 15 received IFF, radar height or altitude information, and standard radar-measured bearing and range information of a target from each radar sensor (or latitude/longitude or other coordinate information received from a radar sensor), and associated the IFF information, radar height information and radar-measured information in step S3.
It should be noted that the received information could have included information from different radar sensors at different locations. Since different radar sensors located in different locations could have provided information of varying reliability and precision about a particular aircraft, the different information from each different radar sensor had to be received, compared, and associated to provide the best possible information about a radar-measured aircraft as explained hereafter. Further, it should be noted that IFF or aircraft identifying data typically indicated information such as mode 1, 2, 3A, 3C, or 4 for example.
The IFF, radar height measurement data and radar-measured information (plots) were thus associated in step S5. Again, this could have involved received radar information, such as bearing and range information of a target, from multiple radar sensors at different locations. The associated information from each radar sensor was then separately stored and later correlated in tracker unit 19 or was correlated, prior to tracker unit 19, regarding particular aircraft or targets detected. Associated plots unit 17 represented the associated, correlated plots.
Next, the radar "tracking" processing function was performed in tracker unit 19. Initially, the tracker unit 19 determined a particular correlation or maneuver window size or area to be measured in step S7. For example, a two mile radius was placed around the coordinates corresponding to the initial radar-measured information received. Next, in step S8, a second or next radar-measured information was received. Then, in step S9, the tracker unit 19 determined whether or not the next received radar-measured information coordinates lay within this determined correlation window. If not, the device returned to step S1 from step S9, since it was determined that latest received radar-measured information was from a target other than a moving object (such as ground clutter, weather, etc.). If that latest received radar information was determined to lie within the previous plot's correlation window, then these two received sets or plots of information were determined to correspond to the same target (aircraft). From the two sets or plots of radar information, a target speed and heading was then calculated in step S11, involving a particular azimuth angle with regard to a predetermined origin, and the target location was displayed via symbol. From the distance and angle, a velocity was then determined. This process was then continued, thereby "tracking" the aircraft in these automated air defense systems.
More specifically, tracker unit 19 compared multiple, consecutive scans of received radar data to determine if a radar "hit" or plot belonged to a moving aircraft and, if so, determined the heading and speed of the aircraft. When multiple radar-measured information inputs were received from multiple radar sensors, each at a different location, the tracker unit 19 functioned as previously stated, except when the geographic coverages of the multiple radar sensors overlapped and a single aircraft was seen by two or more radar sensors simultaneously. Then, an additional multi-sensor correlation task was accomplished. This was accomplished either after IFF and radar height measurement association unit 15 or within tracker unit 19. Thus, if multiple radar sensors were sending data and if those radar sensors had areas of overlapping geographic coverage, then plots/tracks were additionally correlated between radar sensors. However, it should be noted that this processing was both time consuming and often imprecise. In other words, since tracking information was calculated from several inputs and via complex algorithms, the resulting information often caused tracks to move erratically on the display. To correct for these variations, additional time consuming "smoothing" operations were necessary to generate predictable tracks that approximated the aircraft's heading and speed.
Optionally, if radar-measured aircraft altitude information was also received, and/or if aircraft identifying data was also received, then this information was obtained, processed and displayed via symbol in step S13. Then, in step S15, a track identity symbol, track number, and other (selectable) alphanumeric data corresponding to the aircraft was generated (21 of FIG. 1), and was then forwarded to a console 13 of a controller and displayed on a display screen 23.
This normal "tracking" processing function provided the operator with tracking information 24 as shown in FIG. 1, information relevant to a particular aircraft which was detected on radar. However, such information was virtually useless in a tactical engagement situation or to control an aircraft on a landing approach. Further, generation of this information through processing in the tracker unit 19 for example, was extremely time consuming. Specifically, steps S7-S13 were particularly time consuming. Thus, display of a particular aircraft was delayed, and thus a real time display (necessary during the aforementioned tactical engagement or landing control situations) was not possible.